Progress M-27M re-enters over the Pacific as Russia evaluates schedule

The doomed Progress M-27M resupply ship has met its fiery demise on Thursday night, following its problematic launch last week. In reaction to the loss, Russian planners are evaluating changes to the near-term schedule, including a slip of Soyuz TMA-15M landing’s to June 11-12, moving Progress M-28M’s launch up to the beginning of July, while Soyuz TMA-17M launch is likely to be delayed to the middle of July.Progress Farewell: *Click here for Full Coverage*

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The final leg of the ascent to orbit, utilizing the Soyuz 2-1A third stage driven by the RD-0110 engine, appeared to proceed as advertised, with live coverage noting no issues as the Progress separated and stretched out its power-generating solar array panels.

Problems were first observed when uncertainty over the KURS system status resulted in Russian controllers opting to move from the six hour trip to the Station to the traditional two-day rendezvous.

The goal was to use the extra time to troubleshoot communication issues between controllers and the spacecraft, ahead of providing orbital parameters to allow the ship to complete its rendezvous with the orbital outpost.

What was certain was Progress’ fate, ending its short life via an uncontrolled destructive re-entry, with the only remaining question being when and where.

Due to the numerous parameters involved with the orbital mechanics of such an off-nominal End Of Mission (EOM) event, such an entry prediction requires a large amount of calculation, with the window of entry shortened the closer the vehicle comes to the end of its life.

“The team at ESA’s Space Debris Office are providing regular reentry estimates to ESA Member States based on analysis of radar tracking data provided by our US partners, enhanced with data from Germany’s TIRA tracking radar (operated by Fraunhofer FHR),” noted the European Space Agency, as they monitor the track of Progress M-27M.

Observations noted that Progress is experiencing a very fast rotation rate of around one revolution every 1.8 seconds.

“As of Thursday morning, we are forecasting an uncontrolled reentry by Progress M-27M anytime between later in the evening today (Thursday) through to mid-day tomorrow, 8 May,” ESA added.

“The current uncertainty is due to the unpredictability of the drag forces working on the vessel and is a standard feature of such predictions. Any reports claiming precise re-entry times and locations at this stage are speculative.”

The main predictions came from the US side, with NORAD’s timeline refined throughout the final orbits, before Roscosmos “confirmed” of the destructive re-entry of the vehicle resulting in its demise at 02:04 UTC over the North Pacific Ocean.

However, there is still some uncertainty as this region is out of the reach of Russian Ground Stations, resulting in no live tracking. A defined entry time is likely to be forthcoming from NORAD during Friday. That resulted in an updated re-entry time of 02:20 UTC, still over the Pacific Ocean.

Most of Progress will have been destroyed during entry, with any surviving parts highly unlikely to threaten people on the ground based on probability, had the entry occurred over land. However, with the ocean re-entry confirmed, Progress’ demise proved to be uneventful, contrary to some dramatic tabloid reports.

Schedule Evaluations:

Roscosmos is understood to be deep into evaluations for the near-term schedule for their Visiting Vehicles, with changes being discussed with the International Space Station partners.

The ISS recently enjoyed a successful reboost of its orbit via the Rendezvous and Docking (R&D) thrusters on the docked Progress M-26M, in order to set up phasing requirements for Soyuz TMA-15M landing that is on the schedule for May 13. The burn duration was 12 minutes, 17 seconds with a Delta-V of 1.34 meters/second.

Roscosmos are also evaluating the potential to advance the Progress M-28M launch to the beginning of July.

This launch would not be impacted by investigation results that point to an issue with Progress M-27M’s Soyuz 2-1A rocket, as the next Progress is set to ride on the Soyuz-U carrier.

Also noted in the evaluations is the potential to delay the Soyuz TMA-17M launch – lofting Oleg Kononenko of Russia, Kimiya Yui of JAXA and Kjell Lindgren of NASA – until the middle of July.

Such changes – which remain unconfirmed at this time – hold the potential to impact on the wider Visiting Vehicle and ISS schedule, impacts that will be explored in an upcoming article by ISS Editor Pete Harding, should the changes be confirmed.